Increases in carbon values would reduce the Present Value of Benefits (PVB) for the scheme and could have a minor impact on the BCR. Greenhouse gas impacts are presented in Section 10.4 of the Analysis of shortlisted options document as part of the economic appraisal. Across all the options, the value of greenhouse gas impacts is around 10% of the PVB. As an example, were the value of these impacts to increase by 50%, it would result in around a 5% decrease in the PVB and the BCR. In practise, this would mean a reduction in the BCR of no more than 0.1 (e.g. if the current BCR is 2.0, it would reduce to 1.9).